[dns-operations] check if a domain has been registered via DNS

[John Levine]

In article <3358ae00-e21d-92b3-19df-dd3fa527c9c4 at vodafonemail.de> you write:
>if rcode is NXDOMAIN then domain not taken. if rcode is NOERROR then 
>domain has taken.

If the domain exists in the DNS, it's in use, but if the domain
doesn't exist in the DNS, it may be available or it may not.  There
are many states that aren't available but don't publish NS records.

R's,
John